How to enable two-factor authentication?

To enable this account security feature, after logging in click on the “Account” link and then on “Enable two-factor authentication” button. You will be presented with a code which you should enter into your phone. In response, an app on your phone will generate an authentication code which you should enter back on the website to confirm that the phone has been configured correctly. Once this procedure has been completed, two-factor authentication is enabled. Before turning on two-factor authentication, please install the Google Authenticator app or compatible app on your phone. The list of mobile platforms on which this app can be installed can be found in this article.